1. Field of the Invention
This invention relates to spark ignition internal combustion engines which run unattended, continuously for long periods of time.
Typical operation of such engines are irrigation engines used for agricultural purposes, and a person having ordinary skill to which this invention relates is a farmer or a mechanic specializing in repair of agricultural equipment.
2. Description of the Prior Art
In agricultrual operations today, much of the land is irrigated from wells. Normally, to pump the wells requires a power output readily supplied by automotive spark ignition engines. Ordinary automobile engine having about 300 cubic inch displacement have found commercial use and ready acceptance for this service. These engines are equipped with low voltage D.C. electrical systems, i.e. 12 volts D.C. In commercial use, the engines are operated at speeds between 1,400 rpm. and 2,400 rpm. Normally they are cooled by the water pumped, thereby eliminating the power required by a fan drawing cooling air through a radiator. The engines are also normally operated for over 24 hours continuously and normally operated about seven days continuously.
Because the engines operate for over 24 hours unattended they have "kill" switches attached thereto. These kill switches are connected to the electrical system so that if the temperature exceeds a preset amount, the engine is killed. These switches are also set so that if the oil pressure falls below a preset minimum, the engine is killed. Sometimes these automatic switches will have a simple water flow meter so that if there is a cessation or irregular flow of the irrigation water pumped that the engine will be killed.
As stated before, such engines are in wide spread commercial use, and on the whole, satisfactory. However, problems arise from two main sources. Since these engines are located in remote locations and unattended, difficulty is experienced by thieves stealing the batteries from the engines.
In addition, the electrical system requires frequent service. By electric system is meant to include the voltage regulator, the battery, and the generator as well as the distributor and starter. Normally, commercially available voltage regulators and batteries are not particularly adapted for continuous operation without the current being taken from the battery as in normally automotive use. Of course in normal automotive use, there are lights and horn attached to the battery and the battery is frequently used to provide starting current.
Therefore, in the peculiar stationary continuous operating usage, the batteries and voltage generators fail far more often than in normal operative use, for which these elements were designed.
Also, often in agricultural use, the equipment is exposed to more dust and dirt than in normal operative use. Therefore, the brushes of the generator often are subject to excessive wear and fail more frequently than in normal operative use.
In normal use in these agricultural instances, the battery upon the stationary engine is not used for starting purposes. Since the engines are infrequently started, the farmer normally experiences easier starting operation to use a booster battery. i.e., normally, the farmer will arrive at the stationary engine in a pickup truck and will attach jumper cables from his truck battery to the irrigation engine and start it from the battery upon his pickup truck. That is usually more satisfactory than depending upon the battery or stationary engine. Often, the farmer will use a 24 volts (obtained from two 12 volt batteries) to start an engine normally operating on a 12 volt electrically system inasmuch as it starts quicker and easier in such a fashion.
Applicant is aware that commercially on the market there are magneto conversion kits. By these, a magneto is attached to the engine and the battery is eliminated. However, the kits commercially on the market are expensive and also require the use of a special distributor and special spark plugs.